Lock-out for extension or party-line telephones.



T. G, MARTEN 8i]. ERECKSON.

LOCK OUT FOR EXTENSION 0R PARTY LINE TELEPHONES.

APPLICATION FILED 02mm. 1905.

1,151,545. Patented Aug. 24, 1915.

a SHEETS-SHEET 1,

i .1. avg-M556 I z/zlfm" WW W 4 T. s. MARTIN & L'EBICKSONL LOCK OUT FOR EXTENSiON OR'PARTY LINE TELEPHONES.

' APPLICATION FILED DEC-13,1905- 1,151,545. V v Patented Aug. 24, 1915.

8 SHEETS-SHEET 2.

' lmmul Manage;

T. G. MARTIN & J'. ERICKSON.

I LOCK OUT FOR EXTENSION 0R PARTY LINE TELEPHONES.

APPLICATION FILED DEC. 18. I905.

Patented Aug. 24, 1915.

a sHuw-suan 3 T. e. MARTIN 1 JfERICKSON. LOCK OUT FOR EXTENSION 0R PARTY LINE TELEPHONES.

' APPLICA TION FILED DEC. 18. 1905. 1,151,545

T. G. MARTIN 8L1. ERICKSON.

LOCK OUT FOR EXTENSION 0R PARTY LINE TELEPHONES APPLICATION FILED DEC. 18. 1905. I 1,151,545, PatentedAu .24, 191;).

8 SHEETS SHEET 5.

, ,h 54 .o mm, 1. 5/5

. I l Ill 550 L T. G. MARTIN 64 J. ERICKSON.

'LOCK OUT FOR EXTENSION 0R PARTY LINE TELEPHONES. APPLICATION FILED DEC. 18.1905.

Patented Aug. 24, 1915.

8 SHEETS-SHEET 6.

F j- W- 5% 411 5 T. a. MARTIN w. ERICKSON.

LOCK OUT FOR EXTENSION OR PARTY LINE TELEPHONES.

APPLICATION FILED DEC. 18. 1905.-

. 1,1 5 1 .5450 Patented Aug. 24, 1915.

B SHEETS-SHEET 7.

T. G. MARTIN & J. ERICKSON.

LOCK OUT FOR EXTENSION 0R PARTY LINE TELEPHONETS.

Patnted A110". 21, 1915.

8 SHEETS-SHEET 8.

APPLICATION FILED DEC. 18, 1905.

in at any merino snares PATENT OFFICE.

TALBQT Ct. MARTIN AND JOHN nzeicxson,

OF CHICAGO, ILLINOIS, .ASSIGNORS, BY

MESZIE ASSIGNMENTS, TD FIRST TRUST AND SAVINGS BANK, TRUSTEE, OF

CHICAGU, ILLINGIS.

LOCK-OUT FDR EXTENSION OR PARTY-LINE TELEPHONES.

1 9 51 543?, Specification of Letters Patent.

Patented Aug. 24,

Application filed December 18', 1905. Serial No. 292,188.

To (ZZZ whomz't may concern Be it known that we, TALBOT G. MARTIN and Jon): lihncnsox, both citizens or" the United States of America, and residentsof Chicago, Cook count Illinois, have 111- cnted a certain new and useful ment in Lock-Outs for Extension or Partylline Telephones, of which the following is a specification.

()ur inyentirm relates to telephone systems in general, but more particularly to automaticior semi-automatic telephone systems, and especially to automatic or semiautomatic telephone systems in which the subscribers may accomplish certain switching or trunking operations at the exchange or central station by simply transmitting one or inm'eelectrical impulses to the said exchange or central. station, as, for example, by momentarily grounding a subscribers line at the sub-station.

Still more specifically considered, our in- Tontion relates to sci-called extension or party-line telephones-that is to say, it' re lates to arrangements of that character in which a plurality of sub-stations or subscribers telephones are connected with av single line, cithcrin the form of extensions from a main or master telephone, or simply as subscribers on an ordinary party-lins In such cases, it is evident that unless some provision be made to the contrary all of the subscribers connected with the line can listen-in and hear the conversation. which may be going on with any particular subscriber on the line With either extension or party-line telephones his listening-in of a third party is, of course, an undesirable thing, and renders the service to such subscribers more or less unsatisfactory for obvious reasons.

Generally stated, therefore, the object of our invention is the provision of an improved construction and arrangement for preventing a, third subscriber from listening time when another subscriber on the same line is using the circuit.

Special objects or". our invention are the provision of an improved lock-out box adapted to be associated with the main or master telephone of an extension telephone arrangement, and whereby when a call is received, and the operator at the master tel,- phone signals the crlled subscriber at one of Improve-- and any other subscriber.

the extension telephones, there Will then be no possibility whatever of any of the 'other subscribers being allowed to listen-in or dis turb the connections until after the twcl subscribers who are talking are through using the line; the provision of an improved con- 'struction and arrangement whereby all calls ferent calls are then extended or forwarded to the different extension telephones; the provision of an improved construction and arrangement whereby it is not only possible for the user of any extension telephone to automatically sever the connection between the line and all other and between the line and the master telephone as well, but also to then automatically restore all of the extension telephones and I the master telephone in connection with the line as soon as he is through using the latter, and as soon as he hangs up his receiver; and the provision of tures or improvement "tending to increase the generalefiiciency and serviceability oftelephone apparatus of this particular character. v v

It is evident that the features and'advanlanes of ourinvention are applicableto multiple, automatic or exchange systems.

To the foregoing'and other useful ends,

extension telephones,

certain details and feasemi-automatic telephone i our invention consists in matters hereinafter set forth and claimed.

In the accompanying'drawings, Figure 1 1s atop View of our extension telephone lockout box with the cover removed. Fig. 2 is a side elevation of the-same, looking-to the-left. Fig. 3 is a similar'viewfllookingtoward the right. Fig. JG-shows diagrammatically the look-out box with one extension telephone andthe master telephone connect ed. Figs. 4 and 5 taken grammatically a. sub-station connected with together show an a first'selector, connector and [called in Fig. 4:.Fig. 6 is atop view of a-portion buttons employed at Fig. 11 is Fig. 12 shows certain, other details in coni station #120,

' tains transmitter the primary winding 9 of the inductlon-coll ductors;

of the look-out box, showing a number or" relays with some of the ad oining mechamenu in a locked-out position. Fig. 7 18 a view of the same details with the mechanism released. Fig. 8 is an end view of saidde- 1 tails. Fig. 9 shows the terminals to which the telephones are connected. Fig. 10 is a detail sectional view of one of the pushthe master station. a top view of said push-buttons.

nection with a signaling-bell individual to the lock-out box. Fig. '13 is a diagrammatic perspective of the firstselector, while Fig. 14 is a similar view of the connector.

The sub-stations employedin. connection with systems of the class in question may be of any well-known or suitable type. Subfor instance, is at once identified by the peculiar hook-switch 2 which comprises a number of cam-like arms 3, 5 and 3'5. A local primary circuit that con- 7, the batteries 8 and 10, comprises also two circuit-closing springs 11 and 12 which may downward, or brought into contact upon the upward, movement of the switch-hook, when the latter moves about the pivoting terminal 13; This is'done directly through means of a cani-armfi which acts upon the first of said spr ngsspring 11.

The secondary circuit comprises in turnthe secondary winding 14: of the induction-coil 10, in series with the receiver '15, the signaling-button springs i6 and 17, and two secondary cir cuitsprihgs 18 and 19 by means of which the said-seconoary circuit may be main tained opened ,or closed, depending on whether the switch hook up or down. The ringer-circuit at said station includes the .ringer 20 and the ringer-spring 21 in series, and is bridged. across the line-con- When the hook is down the arm 42 engages with the ringer-circuit-spring 21 and completes, at such time, the ringer-circuit at said station. Between the ringer-circuit-spring 21 and the secondary circuitspring 19 a non-conducting piece is inserted, so that said springs may exert pressure on each other and still be kept insulated from each. other. Y7 hen the spring 21 is depressed the spring 19' follows and the connection between, the latter and spring 18 is severed. l/Vhen the hook is up the cam-armb allows the spring to make contact with the spring 23, and thereby controls the continuity of a ground-circuit between the ground ost 2d and the ground G "The releasing or the exchange apparatus is accompiished through the use of. the release-springs 25,26 and two of which (26 and 2!) conbe separated upon the tact-point menses nected each one with one of the line-conductors, while the third oneis connected to the ground G when the springs 22 and 23 are closed. When the switch-hook is'drawn down the release-springs 25, 26 and 27 are forced into union by the release-cam-arm 3, which latter engages a laterally-projecting piece on the upper extremity of the spring 27. Whenever the hook nears its lowest position, said arm 3 disengages from the said spring and permits all of the release-springs to again separate. The calling device is represented by the push-buttons 28 and 29, two springs 30 and 31, two contact-points 32 and 33, and a ground-post 24. The sub station is also provided with a signalingbutton as which is designed when pressed to separate the spring 16 from the contactpoint '17 and to force it onto the contactpoint 35 instead. The banks and trunk-lineterminals are supported in any suitable manner beneath the switch-"frames, and with any one of said trunks a switch may make connection by means of spring-contact-arms or wipers of well-known design.

In. Fig. 13, in connection with the firstselector, are shown the line and private banks 50and 51, respectively, one above the other. Through the former, line-trunking is done; through the latter type of bank the secrecy of the system is maintained, and certain vital and well-known operations of restoration accomplished. The switch-shaft 52 is situated on the front part of the switch, and on its lower part it carries the linewipers 53 and 54-, within range of the bank oi line-contacts that form the line-bank 50, and just above the said line-wipers is located, within range of the private-bank contacts of the private-bank 51, the privatewiper 55. All of these wipers are not-only insulated from each other but from the switch-shaft as well. At its middle portion theshaft carries a cam 56 which, being of the split sleeve design, is tightened to the shaft by a screw 57. a hub-like piece 58 that has a large lower section on which a number of longitudinalteeth 59 are out. The upper section of this hub is smaller than the lower and has cut on it a set of circular-teeth 60 which are traversed by a groove or s1ot'61. .This' groove 61 is designed to receive the bent end of the so-called shaft-support 62, which end receives the weight of the shaft during rotation of the latter, andprev'ents it1fromj rotating unless said end is opposite one of the troughs of the circular-teeth. Still, higher up the switch-shaft has fastened to it the nornial-post-arm 63 which, when the' is in its lowest position, keeps the offnorinal spring 64- separated froin the contactpoint 65 and in contact with the con: I

he shaft" is .inaintained in its normal. rotary position by the coil-spring Just above the cam is the switch 1 frame.

67, which latter has inner end fastened to the shaft and its outer end he normal-post 68. The longitudinal hearings on the shaft are not shown at one them is located between the prix ate-wiper and the cam 56, and the other between the upper end of hub 58 and norm-al-posbarm $25, said bearings being titted to the switch frame. The movements ot' the shaft, which are produced by electro-m" "etically-operated ratchet and pawl me Jiism are vertical and rotary, and each in exit must take place independently at the other. lly these movements th vipers may be carried into engagement in any one. oil liundred contact-points ustitotetlic pri- Vate and line banlrs. is. 1 contacts 1 ton horile capable oil zontal rows, the shaft ten vertical steps, and rotary steps. The vertical in shaft is produced by the ver tli-lli'lii-i elil" 69, which latter when magnetized causes armature to force the s) spring 72; While the n sults indirectly from the i tic-n of rotary-lineaelay 73 when, cnrough i mature 74, it presses the springs into contact. Normally, thcswitch-shaft so rests that the wipers it carries are one step lower than the lowest of their respective banks, and one step the left them. Now, when the crtioutline-relay 1S magnetized-the verticalm ncl; 76, which is composed of two coils and 78, also magnetized. This last magnet has an arina ture 79, known as the tioabarmatare, which has projecting from it a so-ca lcd rertical-armSO that carries pivot I, stened to its endz'a pawl 81 li'IlO'Wil as the verticalpawl said pawl being perly to engage one of tliecircular te oil at each vertical movement of the verticalarmature. This vertical-pawl is held in normal position by the retracting-spring 82 suitably fastened by one end to the bad: of the pawl 81 and by the other to the vertical arm 8G. The vertical-armature is providedflalso with suitable retracting-spring 83 that restores said armature after it has been raised. The vertical-arm carries an Lshaped piece 84 on its under side that assists in the unlocking of the switch when it is first brought into use. This L-shapeol piece forlis over a ll 85 known asthe release-link, which latter is fastened by one end to the release-armature 86 of the releasemagnet 8?. The release-magnet has-assigned to it the otliceof restoring the switch to its normal position after it has been operated. This magnet is composed of two coils like the vertical-magnet, but only one coil. is shown.-

The releasc-armature like the of all of the other magnets is su seer cor? in normal position away from the releasemagnet-polc-piece by the retracting'spring The forward end of the release-link 85 broadens out, and in this broadened section a square opening 89 is provided in which a lug 90 on the double-dog 91 is caught when the release ofthe switch takes place. This double-dog is pivoted on the switch-frame in a vertical plane and swivels about an through. the pivots 92 and has formed on its front part two dogs 93 and 91 that are de signed (the first one) to engage with the circular-teeth ('10, and (the last one) with the longitudinal-teeth 59. side of the dmiblc-dog a release-rwm 95 no jcets downward and assists in the restoration of the switch. The tirst-selector also comprises an arm 96. known as the sideswitclrarm, that may be rocked about avertical axis which passes through the pivots To the left 01. said axis the arm U8 extends marwardly, and on the end of this aim the link 99 is pivotally secured by one end of the rel 'e-arm 95, the end of the latter being of an inverted T-shapc, while the end of the former is bifurcated. Still nearer to the left end of the side-switch-arm 96, a perpendicular pin 100 holds securely four wipers 101,102, 103 and 104- known as the side-switch.-wipers. These wipers are insulated from each other and from the supportingpin to which they are all rigidly fastoned. The said wipers are rigid with the pin and the pin is rigid with the side-switcharm 96. Said arm and appended parts are known as the sidcswitch. When the sideswitcli-arm is rotated about the pivots 97, the side-switch-wipers and the side-switch as a whole will more. The right end of the sideswitch-arm is drawn out into a finger 105 known. as'the escapement-finger, that Works in conjunction with a tooth-escarpment herein cscribed. At the base of this finger a forwardly-bent lug 106 is designed to limit the rocking movement of the'side-switch be-. fore the shaft is rotated out of its rotary normal position. If the rotary-line-relay presses the spring 75 onto the ground-spring 72, the privateemagnet 107 is energized as ,a result. This last magnet is usually fastened to small privatemagnet-frame that is not shown, and which is fastened to the main switch-frame. Said magnet has an armature 108 that wor'ksin a vibratory manner about a horizontal axis Which passes through the supporting-points 109. This armature is formed with a rearWardly-projecting arm 110, the latter having two fiat surfaces in an approximately horizontal plane. more, the end of said arm is bent downwardly at right angles and carries certain mechanical details, namely, a lateral arm 111 From the lower Furthcr- Cir signed that escapement which includes two flexible springs 115 and 116 each of which is riveted at one end to the arm 110, one on the upper side and. the other on the lower. The upper spring is straight and has formed on its end two tootl1-projecti.ons 11? and 118 which extend down, while the-other one is bent down a and at right angles again to the front. This double angle on the lower spring is so dethe latter may clear the bent portion of the private-arm, against which portion said spring rests with a suitable degree of tension, and so that there may be space in front of said bent portion-to receive two other tooth-shaped upwardly projecting pieces 119 and 120 that are formed on the forwardend of the escapeinent-spring 116 and which are situated in juxtaposition to the upper teeth, but slightly to the rearward 'of them. A retracting-spring 121 suitably located holds said armature normally away from, the private-Inagnet-polepiece. WVith this construction, if the pri- "vateanagnet is energized once, the privatearmature is drawn down once and restored. By this operation the escapeinent-finger 105 first passes from behind the tooth 119 to the rear of the tooth 11'? at the downward stroke of the private-armature, and then from behind the latter tooth at the return stroke. As soon as the escapeinent-fingfer clears this last tooth the retracting-spring 122 draws the side-switch to the second position where it is stopped when the lug 106 strikes the cam 56. When the side-switch passes to the second position it carries the wipers 101, 102, 103 and 10 1 from engagement with the contact-points 128, 124, 125 and 126 and into engagement with the contact'points 127, 128, 129 and 130. Then the "rotary-magnet 131 is energised as soon as the wiper 101 finds the contact-point 127. This latter magnet is composed of two coils 132 and 133.

The rotatingmechanism of the firstselector consists of the rotary-armature 131,. a. circuit--interruptingarm 135 that] works in conjunction with two interrupter- -1- 11 "v l i-t .---;1'- springs in an 0, ll, 10 my anna nre finger 1538 that exercises certain controlling influences over the private-armature 108, and lastly the rotary-arm .139, This arm 139 carries'pivotallyv supported on its forwardv end the so-called rotary-pawl 140, and

said pawl has attached to its reanend a small coiled. spring 141, the other 'end of which latter is fastened" to the rotary-arni, and, whiclr'always restores the rotary-pawl to its normal position; At each rotary step of the shaft the rotary-locking-arn1 steals behind one of; thelongitudinal-teeth and locks the slietttffiaid' locking-arm and cir- (ruler-teeth form circular-"locking device -h--".viper 101 the re rotary-magnet 131.is the rotary-armature 134, thereby forcing the rotary-pawl 140 onto thelongitudinal-teeth 59. The shaft is rotated one step by the time the rotaryarmature 134i strikes the rotary-magnet pole-pieces. The energizing-circuit of the rotary-magnet includes the interrupter-, springs 136 and 137, but when the rotaryarmature is attracted, and, therefore, when vtooth 120; then as the rotaryermature 1S drawn down the rotary-magnet 131, the rotary-arinature-fihger 188 depresses the private-armature,108, causing the finger 105 to disengage from the tooth 120 and advance against the tooth-118. As the rotary-arma ture returns to normal, as stated, the pri vate-arinatute. on following the finger 138, permits the finger to escape from the tooth 118, thus permitting the side-switch to pass to third position with the finger 105 resting 8'9311151; the side-switch-stop 148. T he side-switch-wipers 101, 102 103 and 104 are then, respectively, on the contact-points 143, 1 14;, 1&5 and Attention has been called to the banks that are located under the switch parts and in position in front of the line-Wipers and the private-wipers: The terminals of the private-bank are each one electric conducting piece; but the terminals of theline banks are each made of two metallic pieces, one over the other, and insulated from each other When the shaft is raised and ro tated, the wipers engage with the contacts of their respective banks, the private-wiper with those of the private-bank and the linewipers with thoseof the line-bank. After the switch has been operated it can be released by the energizing of the release-magnet 87, Whichenergizing results if the linerelays 69 and 73 are magnetized simultaneously, or if the back-release-relay 147 that controls the back-rolease relay-springs 14S (and 149 is ener ized." The circuits that are brought into p ay under vthese conditions will be traced hereinafter. l When the release-armature is drawn back,- after the release-magnet loses its m'agnetiz ing force, the double-dog' is drawn away s from the shaft; Said shaft, when raisedand, rotated, rests on the shafts-est 62,";1s previously stated, and then when-left to the back v pull of the coiledspring 67.1'OtatS back on the said shaft-rest until the normal-postarm 58 strikes the normabpost 68. The shaftrest then enters the channel 61 that traverses the circulanteeth, and leaves the shaft to fall to its normal position by its own Weight.

and vertical line-relays 73 lar to those .of the The first-selector is pro- .vided in addition with a bridge-cut-ofl-relay 15.0,.the armature 151 of which is adapted to separate the bridge-cut-o1l'-relay-springs 152, 153 and 154. The former two (152 and 15,3) constitute the-terminalsof the rotary and'69, respectively, while the latter .(l) is connected battery B.

Fig. 14 shows the connector 0 which has many'of its parts and circuits very simifirst-selector. The switch-shaft 200 is'identical with the switchdirectly with the non-grounded terminal of shaft of a firstselector and the line- Wipers 201 and 202, the private-wiper 203, the cam %,the longitudinal and circular teeth 205 and 206, respectively, thenormalpost-arm 207and the coiled spring 208 are at once recognized. The shaft-rest 209 and normal-post 210 are well-known, as well as the verticalmagnet 211, the rotary-magnet 212, the private-magnet 213, the releasemagnet 214- and the verticaland rotary linerelays 215 and 216. The said line-relays 215 and 216, through;theirrespective armatures 21-7 and'2l8, operate the line-rela -springs 219 and 220 with respect to'the line-relayground-spring 221 fol-the same direct'purposethat the line-relay-springs of the firstselector are operated. Furthermore the trunk-release-springs.219= and 220 are at the same-time operated with respccttoeach other. The .verticahnagnet, as usual, controls the vertical movements ofthe shaft through the vertical-armature and the pawl 223 onthe end of the vertical-arm 224.

The latter performs its usual functions through the medium of the L-shaped piece 225 upon the release-link 226. In the connector the release-armature 227 is on the right-hand side ot'the release-magnet2L4, instead of on the left, and the release-link 226 'insteadof being fastened to said armatureis fastened from the pin to the frame of the switch in its usual position under the release-magnet. The method of release in the connector is slightly different from that in the first-selector. Instead of the release-link being thrown forward to catch the lug 229 on the double-dog 230,'the latter is kicked by the rclease arma- 'ture 227 and rotated until saidlug passes under the aperture 231, at which instant the link falls over said lug and locks the doubledog. Said doubleedog is the same as the double-dog of the firstselector, and is, therefore, provided with the vertical-dog 232, the rotary-dog 233, the sidc-switch-release-arm 234 and the pivots 235 about which said doubledog swivels.

The rotary armature 236 of the connector is yer-y simple and carries only the rotary-arm 237, which latter, on its end, supports the rotary-pawl 238; but thepriescapement-finger wipers slide back and forth the same way as through the vats-armature 239 is provided with the usual escapement-teeth 240, 241, 242 and 2&3, and with the arm 24% that engages with the private-springs 245, 246, 2&7 and 24:8. The side-switch of the two types of switches being alike, the side-switch-arm 249, the

2-72, and the pivots 253 perform the same functions as those allotted to the similar parts of the switch previously described. Also, the side-switCh-wipers 25%, 255, 256 and 257 and the rows of contact-points 258, 259 and 260; 261, 262 and 263; 264, 265 and 266; and 267, 263 and 269 over which said need no eXpla' nation with regard to their mechanical opcrations and construction. The side-swtich is operated one step at a time each timethe prirate magnet is actuated and is drawn forward at each step by the retracting spring 270. W hen in the third position. the side-switch-arm 249 rests against the side switelrstop 271. The side-switch as a whole is operated by the privatearmature 239 in the side-switch of the firstseleetor, and the private-springs are operated by the arm so that when the privaate-armature is down the springs 2&7 and 248 are together, and when up the springs and 246 are in contact. The connector 'has two oll norinal springs 272 and 273 which are included in the husysignaling circuit, which latter will he pointed out hereinafter. The connector, unlike the "first-selector, has a ringenrelay 275% which, through its armature, controls the springs 275, 276, 277, 278, 279 and 280 by -1ueans of which ringing-current is supplied direction alter theeonnectionthe ability to press the two baelc-.v'elease-1'elay-springs 287and into contact, when the said relays are magnetized simultaneously.

prises four cut-out relays 300, 301, '5" and 303 of the same make. Like the rest or? said relays the relay has an armature 130i: medium of which the springs 30:; and 305 may be separated from the springs 307 and 303. prises an aughiron-shaped locking-armature 305) \vhirh is subject to the pull of the locking-umgiwt 310, and which is pivoted upon the two supports 311 and in. front of 250, the lug 251, the arm- 'l he loeleout box, as shown in Fig. 7, com- Said box'also eomlIlU BEST AVAILABLE CUP? the. cut-out-relays. Upon said armature 309, i

and at points in front of each one of said relays, there is placed a .locking-ihiger 312, 313, 3H and 315. The armature ot-the relay 300 has an extending finger-like projection 316, thefront end of which is chamfered and so normally adjusted that if the magnet 319 attracts the armature 309 the locking-finger ,312 allotted to the relay in question will tion between the relay-springs under the control of said finger. There is a so-called release-magnet 317 the llll'liltulfi 318 of which extends toward the locking-armature said armature. retained against the 309. On the end of the release-armature 318 there is a notch formed between the extreme end 319 and an enlarged section 320 of the Normally, said armature is pole-piece of the release-magnet by an extra also secured to the locking-armature 309. VVhenever'the locking-armature is drawn up by the locking-magnet 310, the lug from on top of the enlarged section320 into the notch on the end of the said releasearmature. This latter armature, when free, is always subject to the tension of the spring 322, which is sometimes aided by the spring The former engages with an elbow 3252 upon said armature, imparting to the latter atendency to travel to the right as soon as the lug321 clears the enlarged.

pole-piece of the release-magnet and locks the locking-armaturc in its attracted position through the medium of the lug 321. it is evi dent that even after the locking-magnet loses its magnetic force the l(' cl-:ing-armature 309 is retained in its unusual position as long as the release-armature retains the lug 321 Within the notch on its en However, if the 1releas0-1uagnet is magnetized and. the release-armature 313 is attracted against the pull of the spring 322, the armature 309 is restored to its normal position by'the spring tension oftwo sets of springs 32%;and: and 326 and 327, the formerv one of thes'e last two being normally in contact with spring 328, and the latter one withspring 329. These springs. pressingonthe horizontally-disposed section of the locking-armature naturally rotate the armatu re ina direc tion to restorethe lug 321,.to its normal position above the enlarged section32'0 upon the release-armature. Besides the relays each time i the lug 321 that is 321 slips section 320, at which time the release-armature leaves the already mentioned, two line-relays '330'and 331 are used in connection with the lock-out box, each one of which is provided with an armature and 333, mature 332 having the ability when attracted by the relay 330 to force the spring 334 toward the spring 335 and the. spring 336 away from the spring 337; while the arma' ture when attracted by'its magnet forces the spring 335 toward the spring The said springs 334 and 335 and"the armaturcs respectively; the ar-- that control them are so adjusted that not until both of said armatures are attracted simultaneously do the said springs 334: and 335 come into contact. -To the left of the relay 330 and in front of the locking magnet a gong 338 is mounted above the springs 326.

and 327. In connection with this gong a striker 339 is provided and fastened'to the end of a crank-arm 340. This crank extends down from the striker and then at right angles through the hearings 3-ll,then again at right angles to the right, and again beneath the relay330 at rightangles toward the locking-armature 309 in such a way that locking-armature is attracted the striker 339 is thrustronceagainst the bell-338. The mechanism thus described is clearly shown in Fig. 12. r i

. A number of extension sub-stations, like the sub-station E, are afforded access to a line of two conductors connected with an automatic central oilice and terminating in first-selector such ,as first-selector ,1) Such a line isgiven one numher,- and any outside subscriber desiring to communicate with any one of the subscribers of'said line calls in the ordinary way and completes a.

connection. Then, upon signaling, ator at the master station-F. answers. operator inquires'which substation is desired and, being infor1ned, presses either one of the signaling-buttons3al2,.343, 344i and. 345 which are common an oper Said buttonene'rgizes a ringer at the desired station. The party desired then comes and rrmoves his receiver,

to thetelephone him 111 direct connection which act places The to the master telephone.

with the main line-condiuztors, and at the same time cuts the master telephone and all the otl1e1' sub-stat ons (members of said l ne) outof service for the time being and .until he zrestores his receiver to thehook.

For instance, assuming that the line connected vith the master station F is #220, andthat the subscriber at sub-station wishes to communicate with a party atsul.

station E of the line n question lie-will through rmal position the interrupter-springs again rengage, and the energizing-circuit the rotary-magnet 131 would be reestablished were it not that by the time the rengagenient occurs the side-switch has passed into the third position, as described, and the side-switch-wiper 101 is no longer in contact with the contact-point 127. As soon as the side-switch passes into the third position the private-wiper 55 is connected to ground through the conductor 115, backrelease-relay 1 17, conductor 416 sideswitch-wiper 102, contact-point 1 14, to the; This connection is be-- the operation just described, the subscribers the last ef-the first nine to rent one line-conductorsd-OO and 401 are extended, revertical and rotary spectively, through the sidesWitch-wipers 103 and 104: and through the vertical and rotary line-Wipers 53 and 5%, the trunk-lines that lead from the first terminal of the second level of the bank 50, similar to the trunk-lines 116 and 17, illustrated in connection with the tenth termi nal of the same level of the said banks, to an idle connector. The rotation of the shaft 52, however, does not always terminate as soon as the wipers are out onto the first terminal of the level to which they may have been raised. For instance, should there be at the same time nine first-selec tors, each with its wipers engaging a dif of the first nine sets of: trunks of the second level of the banks in multiple with banks and 51, there would he a guarding potential at each one or" the first nine private-barriocontacts of the second row, for reasons similar to those set forth in connectionwvith the first-selector A, when 1 the side-switch of the latter passed. into third position, and when the side-I switch wiper 102 became connected with the 55 ground-contactfpoint 144:. Assuming that tlie first nine 'c'oiitacts of the second level of tlie"abovefde scribed group are connected to ground, then when the calling subscriber grounds the rotary side of the line by pressing the rotaryabutt'on 29, the side-switch trips into" the second position; but the ro tationof the shaft will begin and continue until the wipers have been c'a rried beyond terminals which are as at all other privatebusy that is, onto the tenth ,terminal of the ture is attracted by the rotary-magnet 131,--

and the shaft rotated one step, so that the line and private wipers are rotated into engagement with the first terminal of the second level of theirrespective banks. There being a guarding potential at the first contact which the private-wiper meets, a circuit is completed through the private-magnet 107, which extends from the grounded terminal of battery B, through the privatewiper of whatever first'selector is occupying the first trunk position of the second level, and through the bank multiplyin conductors to the contact-point with which the private-wiper 55 has engaged, thence through the privatewiper 55 and conductor so .i

4:15, winding of the back-release-relay-147,

conductor @169, the side-switch-wiper 102, contact-point 128, conductors 118 and 419, private-magnet 107, conductors 420, 413 and 4-08 to the non-grounded terminal of battery.

B and to ground G. Therefore, when the rotary-armature 134: and finger 138 return to their positions, after the interrupterfinger 135 has destroyed the energizing circuit through the rotary-magnet, the private armature, being attracted, does not follow the said rotary-armature-finger, and, theretooth 118. The side-sw'itch-wiperlOl being,-

therefore, retained in engagement with the step of the shaft 52, because grounded contact-point 127, as soon as the interruptensprings' reiing'age, the energizing circuit through the rotarymagnct 1s once more completed. As a result the rotary armature is attracted again, the shaft is rotated one more step, and the private-wiper is pushed onto theecond terminal of the second level of the private-bank. Said contact-point also being grounded, the energizing circuit through the private-magnet is still maintained, so that the side-switch is not liberated when the rotary-armature again returns to its normal position. Clearly, then, the shaft will be rotated in a step-by-step manner as long as the private-wiper 5'5 continuesto meet with grounded private-bank-contacts. After having been rotatedonto the ninth contact, the private-wiper is then rotated one more step and into engagement with the tenth contact of the second level. This last (5 Meet, being' without guarding potential, th magnet- Upon the its forward stroke, so that the privatearmw ture, when released'by the magnetic force that has disappeared from the private-magnet, falls back upon the rotary-armaturefinger and follows the rotary-armature to normal position. Between the time that the private-armature is released by the privatemagnet and the time when the rotary-armature fully regains its normal position, the escapcment-finger 105, which has, during the rotation of the shaft, been resting against the foremost tooth of the upper escapementspring, disengages from said tooth and passes into the third position, and at the same time the side-switeh-wipe r 101 leaves the contact-point and passes to the third position, in engagement with the contactpoint 143. 1111I)t61'-S1)I'i11g5 136 and 137 rengage, so that the circuit through the rotary-magnet is permanently broken in order that no further rotation of the shaft may take place. The side-switch being in the third position, the subscribers line-conductors 400 and 401 are extended through the vertical and rotary line-wipers 53 and 54, respectively, and through the vertical and rotary trunk-conductors 41b and motor C, as shown in Fig. 5. The subscribers line being extended to the connector, he presses the vertical-button 28 twice for the second digit, and again grounds the verticaMine-conductor twice, and thus twice operates the vertical-linerelay 215 of the connector C. The path of this current may be traced from the ground-terminal G at the substation #120 the spring 30, vertical-line-conductor 400, side} to the ground-post 24, through switcl1wiper 103 of the first-selector A,

contact-point 145, conductor 421, vertical line-wiper 53, trunk-conductor 416, verticallined-clay 215, conductors 421*, 422, 423, 424, 425 and 426 and through battery B to ground G. i

When the vertical-line-relay of the connect-or attracts itsarmature 217 the latter forces the line-relay-spring 219 against a ground-spring 221. As a result, the vertical-magnet 211 is energized twice in succession, and the connector-shaft "200 is raised two steps. The current through this magnot passes from the ground-terminal G through the springs 221 and 219, conductor 42?, private-springs 246 and 245, conductor 428, side-switch-Wiper 254, conductor 429, verticahmagnet 211, conductors 423,424, 425 and through battery B and to ground G. first movement of the verticaharm 224, the release-link 226 is disengaged from the doubiedog 230 by This occurs before the inter 417 to the conthe L-shaped piece 3 225, and the verticai-paw1 223 engages one of theicircular-teeth and raises the shaft so that the vertical-dog catches the shaft in its raised position in a manner described in connection with the first-selector-sl iaft. At the second operation of the vertical-ar mature 222 the shaft is raised a second step and retained there. The vertical-button 28 having been pressed twice, the subscriber again presses the rotary-button 29 once, and by grounding the rotaryeline-conductor 401 causes an energizing-current to flow through the rotary-line-relay 216 of the connector for a moment. The energizingcurrent flows from the ground-terminal G to the groundpost 24, thence over the rotary-line-conductor '401 through the first-selector-sideswitch-Wi1: er 104, contact-point 146, conductor 430, rotary1ine-wiper' 54 rotar trunk-conductor 417, rotary-line; elay 216, conductors 422, 423, 424, 425 and 4 6, through battery B andoto ground G. he rotaryline-relay being thus magneti ed once, its armature 218 is attracted once, and forces the springs 220 and 221 into contact. This last operation closes the energizing-circuit of the private-magnet 213, which circuit extends from ground G through the springs 221 and 220, conductor 431, private-magnet 213, and conductor 426, to the non-grounded terminal of battery B and to ground G. The private-magnet being energized the private armature 239 is attracted once. .The escapementfinger 250 clearing the escape meat-tooth 242 at the downward stroke of the armature, and the upper escapement-' tooth 240 at the return energizing-circuit through the rotary-magnet comesfrom the ground-terminal G and extends, as above, through the springs 221 and 219 to the side-switch-wiper 254, but then passes, instead, through the contact point 259 to the conductor 432 and thence through the rotary-magnet 212, conductors 425'and- 426 to the non-grounded terminal of battery 'B and to ground G. Therota'ryarmature'236 is then attracted ten times, once each time that the rotary-magnet is magnetized. Each time that this armature it attracted, the rotary-pawl 238 engages with the longitudinalteeth 205 and rotates the shaft one step in the same Way that the first-selector-rotary-magnet rotated the first-se1ectorshaft Upon the first circucontact point 259 instead, so

engagement at the time that the rotary-dog reaches the crest of the circular-tooth over which it has to pass at such time; but by the time that the rotary-armature strikes the rotary-magnet-pole-pieces,the said rotary-dog thendrops into locking engagement with the longitudinal-teeth, thus retaining the shaft in its-advanced rotary position. At the first rotary step the, shaft-wipers 201 and 202 and the private-wiper 203 pass onto the first contacts of the second level of their respective banks. At the second step the said wipers are pushedonto the second contact; and so on, step-by-step, until they reach the tenth contact of'their respective banks. The laststepof the calling subscriber in completing his connection is to again ground the rotary-line conductor 401 once by pressing thexrotary-button 29 once. Again, the rotary-line-relay is energized, and again the private-magnet 213 only once attracts its armature 239. The shaft having been rotated so'that the cam 204 no longer forms an obstruction to the side-switch-arm 249,

.at the downward stroke of the private-an mature theescapement-finger 250 clears the tooth 243, and when the private-immature returns the upper tooth 241 is also cleared,

and'at this instant the side-switch springs into third position.

The line-wipers having been previously set on the tenth terminal of the second level of the line-bank 290, which terminal constitutes the terminal of the normal-conductors 433 and 434 that are bridged across the sub scribers line-conductors and 436, it will be seen thatas soon as the side-switch-wipers 2 56 and 257 close with the contact-points 266 and 269, respectively, the extended sub scribers" line-conductors 416 and 417 are The vertical-trunk-conductor 416. connects with the vertical-normal-conductor, 4-33,

switch-Wiper 256, conductor 438 and vertiplaced in connection with said normal-com ductors and, therefore, with the desired line.

through the condenser 291, conductor 437, ringer-relay springs 278 and 279, side- Chi-lll'lGvWlPQl 201; while the rotary-trunk- 'c0nductor417 is connected with the rotarynormal-conductor 434 through the condenser 292, conductor 439, ringer-relay-springs 27 5 and 276, side-switch-wiper 257,,condnctor.

440 and the rotary-line-wiper 202. The passage of theside-switch to the third position not only completes the connection thus described, but at the same time connects, as the side-sWitch-wiper 255 passes onto thecontact-point v263, th private-Wiper 203 with an. mind-terminal G. This connection estab ishes' a guarding potential at the tenth X private-contact. of the second level of the .priYatt-bank 293, and at all other private contacts in multiple therewith, in order that no other connector may be able to connect with the same line as long as said guarding potential is maintained. Furthermore, this guarding potential forces a current through the bridge-cut-ofi-relay 375 of the first-selector D, which relay, through its armature, controls the bridge-cut-ofi-relay-springs 376, 377 and 378. This latter relay, when magnetized, separates the said springs from each other and thereby opens up a bridged circuit that normally exists through the vertical and rotary line-relays 379 and 380 of the first-selector D, across the line-conductors 435 and 436, and at the same,time interrupts a connection between said relays and the non-grounded terminal of battery 'B, which terminal is directly.

connected with the, spring 376. Since the I, i

conductors 435 and 436 are included in the maintalking-circuit, aswill be hereinafter explained, one being on one side, and the other being on the other, it is desirable to, remove all unnecessary bridged connections between them, for obvious reasons. The connection between the calling and the called line having beenestablished, the calling party is now ready to signal the calledline. Right-here it may be stated that if for any. reason the calling line is busy when called, a guarding potential will release the" calling connector. line #220 had been called by any other connector, there would be a guarding potential at the tenth private-contact of the second level of the privatebank 293, said contact corresponding to the trunk-lines 43-3 and 434 that lead irom'the tenth terminal of the-second level of the line-bank 290. Were the said line made busy by reason of the firstselector D being in use, the said private-contact would be connected to ground at the instant that the normal-postarm 381 on the shaft of the 9 first-selector D permits the ofi-normal-spring 382 to engage with the grounded contact-point 383,

by way of the private-normal conductor 441 to the contact-point in question. The private-wiper 203 finding such a guarding potential at the instant that the calling subscriber grounds the rotary-line 401, it is evident that on pressing the rotary-button 29 For instance, if the v for the last time the connector. is released, and the subscriber fails to make the desired connection. The release occurs because of the energization of the release-magfnet under such conditions, while the sideswltch 1S 1n second pos1t1on,-said position being the proper position for the side-switch before the rotary-line-conductor is groundwiper 203, conductor 44:2, sidesWitch-Wiper 255, c0ntactpoint 262, conductor 443, privats-springs 247 and 248, conductors 45 .4 and i the private-magnet, uhieh; latter becomes energized over circu ts previously pointed, out, so thatthe private-springs 217 and 218 are incontact at this time.

The "connector-release-inagnet being energized the release-armature 227 Withdraws the double-dog 230, and the lug 229 is caught and held in the aperture 231 on the end of said release-link. Of course, when the douhie-dog is thus rotated the locking-clogs 232 and 233 are withdrawn from the shaft Which, being left free, is rotated back to Ward normal rotary position by the action of the coiled spring 208 until the normalp0starm 207 strikes the normal-post 211. At that instant the shaft-support 209 enters the channel 291 and the shaft of necessity falls to itsnornial position. The release armature 227, upon rotating the double-dog, also drives the side-switch to its first posi- "tion bymeans of the side-sWitch-link and the doubledog-release-arrn The calling subscriber, thinking. that he has established connection, presses the signalingbutton 34; at his sub-station, with the result that the spring 16 is separated from. the contact point 17 and closedin connection with the contactpoint 3-5, and in this way the verticalline-conductor soc/is connected with the ground G by Way of the groundsprings 22an l'23, The connector' being released, and the side-switclrwiper 254 be ing restored into connection With the contact-point 255, the effect of the energizing of the VertiCal-linerelay at this stage is to raise the shaft of the connector vertically.

By'this action the normal-post-arin permits the'normaLsprings 272 and 27 3 to come into contact and permit a busy signaling current, provided by suitable means, to be sent over the line to the callingsubscribefls station and through his receiver. Said busy signal notifies him t-ha t the desired line 'is busy.. The busy current which is produced in the coil 296 passes through the conductor 446, to the contact-point 272, thence by Way of the spring 273 and conductor 4:47 to the contact point 267, side-sWitch-Wiper 257yringer-relay-springs 276 and 275, conductor 439, con (lenser292, conductor 417, rotary-line-\viper 54, conductor 130, side-switclnWiper 104, ro-

tary-line-conductor 401, spring 31, contact point 38, receiver 15, secondary Winding 14: Of the induction-coil -10, contact-point 17, spring 16, springs 18 and 19, contact-point 32, spring 30, Vertical line conductor 100,

side-sWitch-Wiper 103 of the first-selector A, conductor 421,vertical-line-iviper 53, verit takes a course throu h 502, spring 508, ringer his signaling-button Bl and grounds the ver-- ticai-.linecon(luctor 400, as stated, energizmg the vertlcal-hne-relay 215 of the "eon nector. The armature 217 01 said relay then presses the springs 219antl 221 into en- The side-switch-\v1per being" gageinent. in third position, connected with the contact-point 260, the closure oi said springs energizes as a result the ringer-relay 27 1. The energizing-c1lrrcnt flows from the ground-terminal G through the springs 221 and 219 to the side-switch-wiper 25%,- thence the contact-point 260 and through the ringer-relay 274i through battery B and to ground (l. When the ringer-relay is energized it severe the springs 276 and 249 from all connection and then presses them into contact, respectively,

with the springs 277 and 280. lhc ringer generator H is, by this act, placed across the line-Wipers 201 and 202 across the conductors of the called line. The

ringing-ctu'rent originates in the ringergenerator H and passes from the brush 281 to the springs 280 and and to the sideswitch-wiper 256, conductor 4'38, rert-icab line-wiper 201, normal-conduclor 133, line conductor 1'35, relay 331, conductors 448 and 44!), springs 329 and L7, conductor 50, spring 500, contactpoint 501, switch-hook --50*l-,. contact-point 505, spring 506, conductor 451, springs 326 and 328, conductors 452 and 453, relay 330, rotary line conductor 136, rotary normalconductor 43%, Wiper 202, coiuiuctor 4 10, side-suitch-Wiper springs 276 and 277, through the brush 282 back to tl e generator H, The bell at the master station? being rung, the operator at that station, by reinoving his receiver 507 from the hook 502, interrupts the ringing-circuit at the point be tween the caurariu 50S and the ringew spring 503 and bridges the re" iver across the conductors 450 and 4.51. rib soon as the springs 509 and 510 come into contact the subscribe-r at the master station is in a position to speak with the subscriber at the callstation. These two sub-stations, of

h are each provided with their respective 'll'lClliCtlGIl-COllS 10 and 511. The primary Winding 9 of the fol-me" is included in a local primary circuit with the local battery S, transmittcu' and the local circuitsprings 11 and 12, which latter are subject to the operations of the switclrhool; The primarywinding 512 of the second induction-coil 511 is similarly connected in series With the local battery 512, the transmitter 513, and the local circuit-springs 514Tand Theconnection between the two substaand, therefore,

tions connects in series the receivers 507 and 15 over conductors as follows: from the reswitch-wiper103 of the first-selector A,

contact-point 145, conductor 421, verticalline-wiper 53, vertical-trunk-conductor 416, condenser 291, conductor 437, ringer-relaysprings 278 and 279, side-sWitch-wiper 256 of the connector, conductor 438, verticalline-wiper 201, 433, vertical-line-conductor 435, linerelay 331 of the look-out box, conductors 448 and 449, springs 329cnd 327, conductor 450, contact-point 501, secondary springs 510 and 509, secondary winding 516 of the inductioncoil 511, receiver 507, contact-point 505 spring 506, conductor 451, springs 326 an 328, conductors 452 and 453, rotary-hnc-relay 330, rotarydineconductor 436, rotarynormal-conductor 434, rotary line-wiper 202 of the connector C, conductor 440, sideswitchswiper 257, ringer-relay-springs 276 and 275, conductor 439, condenser 292,1'0- tary-trunk-eonduct or 417, rotary-line-iViper 54 of the first-selector A, conductor 430,

si de-switch-wipei 104, rotary-line-conductor 401, spring 31, contact-point 33 and backto Since the primary circuits the receiver 15. atthe two sub-stations thns connected are energized, and since the primary and secondary windings at each one of the stationsv are inductively related to each other, in a well-known manner, the subscribers at these two stations, through their respective receivers andtransmitters, are able to communicate with each other in the usual manner.

The calling subscriber will then inform the bell 525, conductor 454, springs 518 and 517, 1

and conductor 455 to the other terminal of the batteryJ. The subscriber at sub-station E removesfhisieceiver 526 from the hook 527, which latter permits the springs .528 and 529 to come intocontact. As soon 'as'said springs close together a circuit is established from ground G through relay 30.0, lockingmagnet 310, conductor 456,

springs-337 and 336, conductor 457, springs 323 and 322, conductors 458 and 459, to the non-grounded" terminal of the battery J)- The current energizes, in its flow, the said.

relay 300 and the lockingmmgnet 310. The

Y Iarmature 304 is then-attracted by the coil 300, pressing the springs 305 and 306 away vertical-normal-conductorfrom the coil 300, and placing the finger 316 1 on the side of the'locking-fing'er 312 nearest the springs 307 and 308; and when the arma.-

ture 309 is attracted by the locking-magnet v 310 the connection between the springs 305 and 308 and the springs 306 and 307 is main- 4 tained'. The fingers 346, 347 and 348, however, are met by their respective"look1ng fingers 313, 314 and 315, and the armatures 349, 350 and 351 are pressed in such a dime 362 and 363. As soon as the locking-armature 309 is attracted the finger 321 iscaught' in the notch in the end of the release-arms.

ture 318,50 that the release-armature 318 isfl permitted to be drawn away from the polepiece of the release-magnet 317. At this time the springs 322 and 323 are so arated,

as i and the energizing-circuit through t e relay J 300 and the locking-magnet 310 is interrupted. The locking-armature 309, being attracted, forces the springs 326 and 327,re'- spectively, away from the contact-points 328 and 329, at the same time permitting the spring 324 to engage with the spri which last two springs are normally isen I gaged. The separation of the springs 326 and 327 from the springs 328 and 329 removes the master station F from connection the line-conductors 435 =and 436. Therefore; when the subscriber at the sub with E ready t0 p ak to the subsc jibe r' of the'sub-station #120, only his talking a. paratus of'all the talkingap aratus of an stations associated with the ock-out box is in connection with'the line-conductors 435 a1id 436. Othensub-stations, similarto-sub station E, may be connected to the terminals K, L and M.

The bell 33s is provided with the lock-cat mechanism shown. inFig'. l, and is used asaP F signal for the opera-tor at the master stationfl F so that he may know when the subscriber that he has signaled has: responded. .For, I

jib

instance, when the subscriber at sub-station locking-magnet 31:0, vthe striker"' 339"xs to removes his receiver andcauses'the lockw ing-armature'309 to be drawmu'p by the 1 i115,

tated againstjth""-bel1 338-andyprpduoesasound that assumes the desired Si in. f

From the preceding description -it wi seen that ,as's'oon as the subscriber atic'the 'x f l ll connected with the lock-out box 1 sub-station E answers, all the sl'rb stdtionii.

nected from the main line-c0nductors"435 f and 436, and are rendered-inoperative for the time by their respective lockout-relays; 301, 302 and 303. The necessity for thebell- 338 is evident, sincethe' operator at the'mwl ter station F has no other means of ascer' taining whether the sub-station he-i's sig nalmg responds or not, because if the called sub-stat1cn dong respond the master station; 

